Technical Field
The present disclosure relates to an imaging device including a photoelectric conversion film.
Description of the Related Art
Subjects present in the natural world have a high dynamic range. For example, in the case of an in-car imaging device, the brightness of a subject changes from moment to moment, and the in-car imaging device is required to simultaneously pick up images of a bright subject and a dark subject (have a high dynamic range). To achieve a high dynamic range, Japanese Unexamined Patent Application Publications Nos. 62-108678 and 2008-99073 propose the methods below.
The imaging devices disclosed in Japanese Unexamined Patent Application Publications Nos. 62-108678 and 2008-99073 use a silicon photodiode. In Japanese Unexamined Patent Application Publication No. 62-108678, images different in exposure time (which may also be referred to as “storage time” hereinafter) are synthesized, which allows achievement of a high dynamic range. The approach has already been put to practical use. In Japanese Unexamined Patent Application Publication No. 2008-99073, a dynamic range is extended by synthesizing images obtained from a plurality of image pickup cells different in sensitivity which are arranged within one pixel.
Japanese Unexamined Patent Application Publication No. 2007-59465 proposes a laminated sensor including a photoelectric conversion film instead of a silicon photodiode which may become an obstacle to a high dynamic range.